This invention relates to a unique brake lining backing plate for a disc brake which includes tabs at each end adapted to receive a spring, such that the spring is supported between the tabs.
Disc brakes are widely used in vehicle braking systems. In a typical disc brake system, brake pad assemblies are located on either side of a rotating disc. Each brake pad assembly includes a backing plate to which brake lining friction material is attached. A brake actuator moves the brake pad assemblies toward the rotating disc such that the brake lining friction material contacts the side surfaces of the disc, thus retarding the rotation of the disc.
Certain deficiencies exist with the known disc brake systems. Specifically, during vehicle operation, the brake pad assemblies have a tendency to rattle which can be noisy and can result in premature wear of brake assembly components. To achieve optimum braking performance it is important for the brake pad assemblies to be properly positioned in relationship to the disc. Ideally, the surfaces of the brake lining friction material will be spaced at equi-distances from the surface of the disc. This clearance between the brake lining and the disc is preferably maintained as the vehicle is in operation and as it experiences road load conditions such as accelerations, decelerations, and bumps in the road. When the vehicle is braked, the brake actuator moves the brake pad assembly toward the rotating disc such that the brake lining is brought into contact with the disc. The contact between the brake lining and the disc decreases the rotational speed of the disc thus slowing or stopping the vehicle.
When the actuator is released, the brake pad assembly returns to its initial position and the clearance between the brake lining and the disc is reestablished. If the brake lining is in continual contact with the disc or if the lining comes into contact with the disc during normal vehicle operation, such as when the vehicle goes over a bump, the result is excessive noise, premature wear of the brake lining, and premature wear of the brake disc all of which are undesirable.
Anti-rattle devices, attached to the backing plate of the brake pad assembly, are used to reduce the noise of the rattling brake pad assembly components and also maintains the brake pad assemblies in proper relation to the disc. While anti-rattle devices such as springs have been used to reduce the rattle of the brake pad assemblies, they have not adequately achieved the dual function of maintaining the brake pad assemblies in proper position with relation to the disc while also significantly reducing the noise created by the rattling of the brake pad assembly components.
FIG. 1A shows one prior art backing plate 9 for a disc brake. As shown, tabs 10 are adjacent spaced ends 12 and 14 of the backing plate. Tabs 10 mount an anti-rattle spring 11. The spring 11 is not supported or contacting the backing plate 9 between the tabs 10. As such, there is not as much support from spring 11 for the backing plate 9 as may be desired.
As shown in FIG. 1B, a surface 12 which extends between the tabs 10 is spaced from a bottom surface 14 of the backing plate 9 by a lesser distance than a top surface 18 of a groove 16. Groove 16 receives an outer end 19 of the spring 11. Stated another way, a reference line R which is parallel to the bottom edge 14, and spaced adjacent to the bottom edge 14, is closer to point 19 which defines the location where the tab 10 merges into the top edge 12 than is top surface 18 of groove 16. As shown in FIGS. 1A and 1B, there is no support for the spring 11 between the tabs 10.